<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Synopsis</title>
<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset">
<link rel="up" href="../conversion.html" title="Chapter 8. The Conversion Library 1.7">
<link rel="prev" href="polymorphic_casts.html" title="Polymorphic casts">
<link rel="next" href="history.html" title="History">
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr>
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td>
<td align="center"><a href="../../../index.html">Home</a></td>
<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td>
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
<td align="center"><a href="../../../more/index.htm">More</a></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="polymorphic_casts.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../conversion.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="history.html"><img src="../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="conversion.synopsis"></a><a class="link" href="synopsis.html" title="Synopsis">Synopsis</a>
</h2></div></div></div>
<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>

<span class="comment">// Throws: std::bad_cast if ( dynamic_cast&lt;Derived&gt;(x) == 0 )</span>
<span class="comment">// Returns: dynamic_cast&lt;Derived&gt;(x)</span>
<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span><span class="special">&gt;</span>
<span class="keyword">inline</span> <span class="identifier">Derived</span> <span class="identifier">polymorphic_cast</span><span class="special">(</span><span class="identifier">Base</span><span class="special">*</span> <span class="identifier">x</span><span class="special">);</span>

<span class="comment">// Effects: assert( dynamic_cast&lt;Derived&gt;(x) == x );</span>
<span class="comment">// Returns: static_cast&lt;Derived&gt;(x)</span>
<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span><span class="special">&gt;</span>
<span class="keyword">inline</span> <span class="identifier">Derived</span> <span class="identifier">polymorphic_downcast</span><span class="special">(</span><span class="identifier">Base</span><span class="special">*</span> <span class="identifier">x</span><span class="special">);</span>

<span class="comment">// Effects: assert( dynamic_cast&lt;Derived&gt;(&amp;x) == &amp;x );</span>
<span class="comment">// Returns: static_cast&lt;Derived&gt;(x)</span>
<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span><span class="special">&gt;</span>
<span class="keyword">inline</span> <span class="identifier">Derived</span> <span class="identifier">polymorphic_downcast</span><span class="special">(</span><span class="identifier">Base</span><span class="special">&amp;</span> <span class="identifier">x</span><span class="special">);</span>

<span class="comment">// Throws: std::bad_cast if ( dynamic_pointer_cast&lt;Derived&gt;(x) == 0 )</span>
<span class="comment">// Returns: dynamic_pointer_cast&lt;Derived&gt;(x)</span>
<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span><span class="special">&gt;</span>
<span class="keyword">inline</span> <span class="keyword">auto</span> <span class="identifier">polymorphic_pointer_cast</span><span class="special">(</span><span class="identifier">Base</span> <span class="identifier">x</span><span class="special">);</span>

<span class="comment">// Effects: assert( dynamic_pointer_cast&lt;Derived&gt;(x) == x );</span>
<span class="comment">// Returns: static_pointer_cast&lt;Derived&gt;(x)</span>
<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span><span class="special">&gt;</span>
<span class="keyword">inline</span> <span class="keyword">auto</span> <span class="identifier">polymorphic_pointer_downcast</span><span class="special">(</span><span class="identifier">Base</span> <span class="identifier">x</span><span class="special">);</span>

<span class="special">}</span>
</pre>
</div>
<div class="copyright-footer">Copyright © 2001 Beman Dawes<br>Copyright © 2014-2025 Antony Polukhin<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="polymorphic_casts.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../conversion.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="history.html"><img src="../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>
